1. Field of the Invention
The present invention relates to a method of controlling a gas type clothes dryer. More particularly, the present invention relates to a method of controlling a gas type clothes dryer that continuously detects condition of a flame sensor even after ignition of the dryer, thereby preventing a drying operation from being performed when a flame has been extinguished due to insufficient gas supply caused by failure of a gas valve.
2. Description of the Related Art
FIG. 1 is an exploded perspective view of main parts of a general gas type clothes dryer.
Referring to FIG. 1, the clothes dryer has a drum 1 inside a cabinet (not shown) that constitutes an outer appearance of the dryer.
The drum 1 has a cylindrical shape and is open at both sides. A belt groove 2 is formed along the middle of an outer peripheral surface of the drum 1 such that a belt (not shown) is wound around the belt groove 2 and driven by a separate drive source, and a drying chamber 5 for a drying operation is defined in the drum 1.
The drying chamber 5 has a plurality of baffles 6 formed on an inner surface thereof to tumble laundry received in the drying chamber 5 during rotation of the drum 1.
A front head 7 and a rear head 9 are provided to front and rear ends of the drum 1, respectively. The front and read heads 7 and 9 close the openings of the drum 1 to define the drying chamber 5 while supporting the front and rear ends of the drum 1.
Further, sealing members 10 are interposed between the front head 7 and the drum 1 and between the rear head 9 and the drum 1 to prevent leakage.
The dryer is provided with a plurality of rollers (not shown) at locations corresponding to the front and rear ends of the drum 1 to support the drum 1.
The front head 7 is formed with a through-hole 8 through which the interior of the drying chamber 5 communicates with the outside. The through-hole 8 is selectively opened/closed by a door (not shown).
The rear head 9 is provided with an air supply duct 12 that serves as a passage for supplying air, more specifically, hot air into the drying chamber 5 and communicates with the interior of the drying chamber 5.
One side of the front head 7 is provided with an outlet assembly 13 through which air is discharged from the drying chamber 5.
A lint filter 14 is provided to the outlet assembly 13. The lint filter 14 serves to separate foreign matter, such as lint or dust, from air discharged from the drying chamber 5 through the outlet assembly 13.
A lint duct 15 is provided to communicate with the outlet assembly 13 and receive part of the lint filter 14. A blower 17 is connected to the lint duct 15 and suctions air from the drying chamber 5 through the lint duct 15.
The blower 17 is disposed inside a blower housing 18. The blower housing 18 communicates with the lint duct 15 through one side thereof and is connected at the other side to a discharge pipe 19. Therefore, air discharged from the drying chamber 5 passes through the lint duct 15 and is discharged to the outside through the discharge pipe 19 by force from the blower 17.
On the other hand, the air supply duct 12 is connected to a hot air duct 20. The hot air duct 20 serves to supply hot air for drying operation into the drying chamber 5. For this purpose, the hot air duct 20 is provided with a component which generates thermal energy for heating air.
In other words, an inlet of the hot air duct 20 is provided with a gas nozzle 22. The gas nozzle 22 serves to spray a supplied gas. The gas nozzle 22 is provided with a gas valve which controls supply of the gas. Reference numeral 23 indicates a gas pipe.
A mixing pipe 24 extends from the inlet of the hot air duct 20 and is disposed inside the hot air duct 20 to mix primary air and the gas sprayed from the gas nozzle 22. Here, an inlet of the mixing pipe 24 is located corresponding to the gas nozzle 22.
Inside the mixing pipe 24, the gas sprayed from the gas nozzle 22 is mixed with external air introduced through the inlet of the mixing pipe 24, that is, with the primary air. The mixing pipe 24 is provided at a leading end with an ignition device 26 to generate flame for ignition.
Next, a configuration for controlling the dryer with the above configuration will be described. FIG. 2 is a block diagram of the general gas type clothes dryer.
The general gas type clothes dryer performs drying operation under control of a microcomputer 140. In the dryer, a drive unit is electrically controlled by the microcomputer 140, and sensors for detecting electrical signals output detected signals to or receive signals from the microcomputer 140.
First, a power supply signal, drying operation signal, a drying condition input signal, and the like are input to the microcomputer 140 through a key input unit 100 according to a user's selection, and a dried degree of laundry is detected and sent to the microcomputer 140 by a humidity sensor 110.
Additionally, the temperature of hot air discharged from the drum is detected and sent to the microcomputer 140 by a temperature sensor 120. Further, a door detection unit 130 sends a detection signal to the microcomputer 140 to prevent the door from being open during the drying operation.
Under control of the microcomputer 140, a drum motor drive unit 150 operates a drum motor which generates a drive force for rotating the drum 1, and a blower motor drive unit 160 operates a blower motor which generates a drive force for rotating the blower 17, so that the rotation of the drum 1 and the blower 17 can be controlled.
Further, a heater drive unit 170 operates the heater which supplies a heat source under control of the microcomputer 140.
Next, operation of the general gas type clothes dryer will be described.
When an operation button of the key input unit 100 is pressed with laundry put into the drying chamber 5 in the drum 1 and the door closed, the microcomputer 140 operates the drum motor drive unit 150 in response to an instruction for the drying operation. Then, the belt wound around the belt groove 2 is driven by a separate drive source to rotate the drum 1.
Further, the microcomputer 140 sends a control signal to the blower motor drive unit 160 to operate the blower motor. Then, the blower 17 is operated to suction air from the drying chamber 5 through the lint duct 15. As a result, external air is introduced into the drying chamber 5 through the air supply duct 12.
On the other hand, the microcomputer 140 controls the heater drive unit 170 to operate the heater such that the temperature of air supplied into the air supply duct 12 is comparatively increased to a high temperature when passing through the hot air duct 20.
Further, the microcomputer 140 operates the gas valve 28 to control gas supply through the gas nozzle 22, and controls an igniting operation and an ignition state through the ignition device 26 and the flame sensor 30.
After initial ignition by the ignition device 26, a gas is sprayed into the mixing pipe 24 by the gas nozzle 22 to continue combustion of the gas. Then, heat energy by the combustion of the gas heats the air, which has been introduced into the hot air duct 20, thereby generating hot air.
The hot air is supplied into the drying chamber 5 of the drum 1 through the air supply duct 12. The hot air absorbs moisture from the laundry within the drying chamber 5 and is discharged from the drying chamber 5 through the outlet assembly 13.
Here, the hot air is discharged from the drying chamber 5 through the outlet assembly 13 by the suction force of the blower 17. Further, foreign matter such as dust or lint is removed from the air passing through the outlet assembly 13 by the lint filter 14.
When the laundry is dried inside the drum 1 by such a hot air circulation manner, the microcomputer 140 determines a dried degree of the laundry based on a detection value of the humidity sensor 110. Further, the microcomputer 140 makes a final determination as to the dried degree of the laundry based on the temperature of the hot air, which is discharged outside the drum 1 and detected by the temperature sensor 120, and controls the drying operation based on the determination result.
It should be noted that the aforementioned technique is related to the background art of the invention and is not a conventional technique.
In order to operate such a gas type clothes dryer which uses combustion heat of a gas, it is determined whether the ignition device is normally operated by checking the condition of the flame sensor after operation of the ignition device. If it is determined that the ignition device is normally operated, the operation of the ignition device is stopped and the gas valve is operated to supply the gas, which is combusted to generate the combustion heat for drying laundry.
In such a gas type clothes dryer, although the condition of the flame sensor is initially checked to determine whether the ignition device is normally operated, the condition of the flame sensor is not checked after it is determined that the ignition device is normally operated. As a result, even in the case where the gas is not supplied due to failure of the gas valve, it is determined that the ignition device is normally operated, so that a subsequent cycle can be performed without gas supply.